How can Autoconf help with the transition to stricter compilation defaults?

[Bob Friesenhahn via cfe-commits]

On Tue, 15 Nov 2022, Sam James wrote:

>
>
>> On 13 Nov 2022, at 00:43, Paul Eggert <eggert at cs.ucla.edu> wrote:
>>
>> On 2022-11-11 07:11, Aaron Ballman wrote:
>>> We believe the runtime behavior is sufficiently dangerous to
>>> warrant a conservative view that any call to a function will be a call
>>> that gets executed at runtime, hence a definitive signature mismatch
>>> is something we feel comfortable diagnosing (in some form) by default.
>>
>> As long as these diagnostics by default do not cause the compiler to exit with nonzero status, we should be OK with Autoconf-generated 'configure' scripts. Although there will be problems with people who run "./configure CFLAGS='-Werror'", that sort of usage has always been problematic and unsupported by Autoconf, so we can simply continue to tell people "don't do that".
>>
>
> Is there somewhere in the autoconf docs we actually say this?
>
> I've seen a few instances of folks adding it themselves very
> early in their configure scripts (which is a pain for distros
> anyway) which then ends up affecting the rest.

Autoconf can help with this issue due to GCC and some other compilers 
providing extensions (usually a pragma) to control warnings while 
compiling the C code.  So configure can run without -Werror, but 
Autoconf could help by providing an easy way for enabling -Werror 
while compiling the application.

Of course the above does not require Autoconf since application 
developers can figure it out by themselves using preprocessor logic 
and knowledge of compiler-specific behavior.

If Autoconf is able to help, then the convoluted code can be in just 
one place (in Autoconf).

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
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